Eli5: How does gravity affect time, dumb it down for me as much as possible
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Everything in the universe is constantly moving at c (The speed of light) through spacetime.
This speed is split between movement through space and movement through time, but it always adds up to c. (Movement through space + Movement through time = c)
The more of this total speed you allot to move through space, the less you are using to move through time.
Photons (light particles) move at the speed of light through space, and so do not move through time at all, 100% of their speed is allotted to movement through space.
Gravity warps space in such a way that it takes light longer to traverse it.
The speed of light is a universal constant, so if it takes light longer to traverse that warped space, then time has to move slower.
Here’s an example:
We have a 50ft hallway and it takes you 10 seconds to walk across it.
I press a button which increases the gravity in that hallway enough to warp the space inside of it substantially(Ignoring the fact that you would be crushed by said gravity).
When you walk across the now spatially warped hallway, something weird happens. From my point of view outside the warped space, instead of taking 10 seconds it takes 20.
The hallway is still only 50ft long, and you went at the same speed, but it took you longer to come out the other end.
When I ask you what happened you say “What do you mean? it still only took 10 seconds.”
If it took you longer to traverse the same distance at the same speed the only explanation is that time was moving slower for you(You were effectively moving in slow motion).
You had to allot more of your total speed(c) towards movement through space than you normally would to traverse the warped space, and due to the tradeoff between movement through space and movement through time, in order to do so you had to take that speed from your movement through time.
EDIT: This is also why it’s impossible to move faster than the speed of light(c), your total speed through spacetime can only ever equal c.
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